The lwresd utility is the daemon providing name-lookup services
to clients that use the BIND 9 lightweight resolver library.
It's essentially a stripped-down, caching-only name server that answers
queries using the BIND 9 lightweight resolver protocol rather than the
DNS protocol.
For more information, see
http://netbsd.gw.com/cgi-bin/man-cgi?lwresd+8+NetBSD-5.0
in the NetBSD documentation.